A pinless cycloidal gear is a reduction technology that simplifies the internal structure by eliminating the pin components used in conventional cycloidal reducers. Conventional cycloidal reducers are advantageous for transmitting high torque, but as the number of pin components increases, the internal component configuration and assembly process can become more complex. The pinless structure focuses on overcoming these limitations by removing pin components and improving the efficiency of component configuration and assembly.
This article takes a step-by-step look at the basic concept and structural characteristics of pinless cycloidal gear reduction technology, as well as how it can be applied to robot drive units.
Table of Contents
Definition and Background of Pinless Cycloidal Technology
Key Summary — A pinless cycloidal gear is a structure that removes the pin components traditionally arranged in the housing and engaged with the disc in conventional cycloidal reducers.
Conventional cycloidal reducers operate by placing multiple pins or pin rollers inside the reducer, where the cycloidal disc engages with them to transmit rotational motion. This structure has the advantage of enabling accurate power transmission. However, as the number of pin components increases, the component configuration and assembly process can become more complex, and the number of factors that must be controlled during production may also increase.
Pinless cycloidal technology is a design approach that improves the efficiency of the internal structure by eliminating pin components from the conventional configuration. By implementing the cycloidal reduction principle without separate pin components, it can reduce the number of parts and lower the process burden that may arise during assembly.
This technology emerged to improve manufacturing efficiency and productivity. In particular, in fields such as robotics, automation equipment, and drive systems, where miniaturization, weight reduction, and design flexibility are important, the structural efficiency of the reducer becomes a key competitive factor. Pinless cycloidal reducers are designed to respond to these industrial needs by eliminating pin components and securing a more efficient component configuration and greater design flexibility.
Advantages of a Structure That Reduces the Number of Components
Key Summary — The main characteristic of the pinless structure lies in reducing the component configuration. Fewer parts can simplify the assembly process and reduce structural burdens in production and quality control.
Reducers used in robot drive units play the role of stably transmitting large forces within a small space. In particular, reducers applied to joint drive units must maintain consistent performance even under long-term operating conditions. For this reason, when selecting a reducer for robots, it is necessary to consider not only torque transmission performance but also durability, assemblability, and productivity.
Planetary gears or planetary reducers are widely used in the fields of robotics and automation equipment. Planetary reducers have a relatively simple structure and are generally easier to manufacture, making them advantageous for mass production. The reason planetary reducers are widely used is not simply due to cost. It is because they have a simple structure, are easy to produce, and can reliably deliver a certain level of performance. Thanks to this productivity and versatility, planetary reducers have been used across various industries for a long time.
Recently, the requirements placed on reducers in the robotics industry have become more demanding. Since robots have limited joint space, reducers must be small and lightweight. At the same time, they must reliably transmit force even when lifting heavy objects or performing repetitive movements. In robotics fields that require accurate motion, positioning control and stability during repeated operation are also important conditions. In environments where these diverse specifications are required at the same time, existing planetary reducers may have limitations.
This is why cycloidal reducers are gaining attention in robot drive units. Cycloidal reducers can stably transmit high torque and are advantageous for securing structural stability even in environments where repeated loads and impacts may occur. These characteristics make them suitable for robot joint drive units, where strong force and durability are required within a compact space.
However, cycloidal systems also have challenges that need to be addressed. Depending on the structure, the number of internal components may increase, and each component must be accurately machined and assembled, which can increase the difficulty of manufacturing and assembly. When the number of parts increases, production costs can rise, and small deviations during assembly can affect product quality. In other words, cycloidal reducers have advantages in terms of force and durability, but for broader use in the robotics industry, productivity and assemblability must also be secured.
The pinless cycloidal gear structure is a method that simplifies the component configuration to reduce these issues. Through this approach, it preserves the high torque transmission capability and durability of cycloidal reducers while improving productivity.
When the structure becomes simpler, the number of factors that must be managed during machining, assembly, and inspection decreases. This provides an important foundation for maintaining consistent quality and expanding robot components into mass production.
In the robotics market, each product has different requirements for torque, reduction ratio, size, and application environment. In particular, because the reducer is a key component that has a major impact on the performance and cost structure of robot drive units, a structure that can respond to various specifications while securing productivity is needed.
The pinless cycloidal gear structure maintains the strong torque transmission capability and durability of cycloidal reducers while reducing the number of components and the burden of assembly. As a result, it can support both the performance and mass-production requirements needed for robot drive units.
Why the Pinless Structure Is Being Considered for Robot Joints
Key Summary — The pinless cycloidal structure is a method that reduces the component configuration and supports the design of thin drive units. It can be considered for applications such as robot joints, where both space and load conditions must be taken into account.
Reducers applied to robot joints must stably transmit high torque within limited space. In particular, in structures where joints move repeatedly, such as humanoid robots, collaborative robots, and industrial robots, the size, thickness, weight, and durability of the reducer all become important design factors.
When designing robot drive units, space utilization inside the joint is extremely important. If the reducer is too thick, the overall volume of the joint increases, which can also affect the design flexibility of a robot arm or leg. Therefore, reducers for robot joints require a design approach that can realize a thin and compact structure.
The pinless cycloidal structure reduces the internal component configuration by eliminating the pin components used in conventional cycloidal reducers. This allows the internal structure of the reducer to be configured more efficiently and is advantageous for realizing a thin package within limited joint space.
In addition, when the number of components is reduced, the number of factors that must be managed during assembly is also reduced. Since reducers for robot joints must maintain consistent quality and performance under repeated operation and long-term use, reducing assembly deviations and securing productivity are important. From this perspective, the pinless structure is a design direction that can take both assemblability and mass productivity into account.
The cycloidal reduction method has the characteristic of distributing and transmitting loads across a broad contact surface, making it suitable for robot joint environments where repeated loads and impacts may occur. By applying a pinless structure to this method, it is possible to maintain the high torque transmission characteristics of cycloidal reduction while reducing the burden related to component configuration and space utilization.
For these reasons, the pinless cycloidal structure is a reducer design method that can be considered for robot joint drive units where miniaturization, weight reduction, and thin packaging are important. In particular, it is expected to have application potential in robotics and automation equipment fields that require stable force transmission while efficiently utilizing the internal space of joints.
Bonsystems Application Direction for Pinless Cycloidal Gear Technology
Key Summary — Based on cycloidal reduction technology, Bonsystems is advancing its technology around key features such as the pinless structure, component-reducing design, and compact packaging.
Bonsystems develops drive solutions that can be applied to robot joints, robot arms, and mobile robot drive units based on cycloidal reducer and actuator technologies. In particular, through its pinless cycloidal gear structure, Bonsystems is advancing its technology in a direction that maintains the advantages of conventional cycloidal reducers while improving productivity and assemblability.
Bonsystems’ pinless cycloidal reducers, BSR 070 and BSR 080, feature a structure that removes the pin components used in conventional cycloidal reducers. This provides a foundation for improving the efficiency of the internal component configuration and enhancing assemblability and productivity. While utilizing the high torque transmission characteristics and durability of the cycloidal reduction method, the technology focuses on addressing limitations in reduction ratio responsiveness and manufacturing efficiency.
In addition, Bonsystems’ pinless cycloidal reducers can implement various reduction ratios from 19:1 to 99:1, allowing flexible responses depending on the application environment. They can be used for a wide range of drive conditions, from mobile robot drive units that require lower reduction ratios to robot joints and robot arms that require high torque and accurate motion. This reduction ratio flexibility is an important factor that helps robot manufacturers design drive units suited to the characteristics of their platforms.
Based on this reduction technology, Bonsystems is also developing ultra-compact reducers and actuators. As robot drive units become smaller, robot manufacturers can design joint structures more efficiently and more easily implement the required force and motion performance within limited space. In particular, in robot platforms where the reducer, motor, and drive control elements must be considered together, a small and thin drive unit design is directly connected to overall product competitiveness.
This direction can also be seen in Bonsystems’ BCSA series. The BCSA series is an actuator lineup that combines a reducer and a frameless motor in a compact structure. It is designed in a direction suitable for fields such as robot joints, where both the size of the drive unit and force transmission performance must be considered.
Ultimately, Bonsystems’ pinless cycloidal gear technology can be described as a drive technology that considers the structural efficiency of the reducer, reduction ratio flexibility, assemblability, and productivity together. As demand grows in the robotics market for smaller and lighter joints as well as stable force transmission, this pinless structure and ultra-compact drive unit development direction can become a technological foundation applicable to various robot platforms.
F.A.Q
Q: How is a pinless cycloidal reducer different from a conventional cycloidal reducer?
A: A pinless cycloidal reducer is characterized by a structure that removes the pin components used in conventional cycloidal reducers. This can reduce the number of components, simplify the assembly process, and support improvements in productivity and manufacturing efficiency. In addition, structural simplification can also be advantageous for weight reduction and securing design flexibility.
Q: What are the technical advantages of removing the pins?
A: Removing the pin components simplifies the internal structure of the reducer, which can lower assembly difficulty and reduce the burden of component management. This helps improve manufacturing process efficiency during mass production and also supports miniaturized and lightweight designs for robot drive units.
Q: Why is a pinless cycloidal reducer suitable for articulated robots?
A: Articulated robots such as humanoids, dual-arm robots, and collaborative robots must place multiple joints and drive units within limited space. Pinless cycloidal reducers offer advantages in miniaturization, weight reduction, high torque implementation, and design flexibility, making them suitable for robot structures that require high-performance drive units in narrow spaces.
Q: In what direction is Bonsystems expanding its pinless cycloidal gear technology?
A: Bonsystems is developing ultra-compact reducers and thin, high-torque actuators based on pinless cycloidal reduction technology. Through this, the company aims to respond to various robot drive environments, including humanoids, AMRs, dual-arm robots, and collaborative robots, while strengthening its competitiveness in robot joint and drive unit technologies required in the era of Physical AI.
